FREQUENCY INVERTERS

Machine and plant manufacturers are constantly expanding the range of functions of their products, and are increasingly relying on stepless speed control in places where previously a fixed speed had to suffice. For this reason, frequency converters are a rapidly growing field of mechatronic drive technology.

Before the development of microcontrollers, speed-controlled drives were usually implemented using DC technology. However, DC motors are much more expensive than the dominant three-phase squirrel-cage motors, so either a fixed speed was used or two speeds were used, which could be provided by a pole-changing motor (e.g. Dahlander). Stepless speed control of a three-phase drive could also be realised mechanically. However, planetary control gears are only suitable for a limited number of applications due to the smaller control range, the speed-dependent torque and the adjustment mechanism.

In the mid-1970s, market-ready microprocessors were finally developed and digitally controlled speed regulation entered the industry. The new frequency inverters made much more efficient speed control possible. Inverters are themselves wear-free, and also reduce wear on the machine. In addition to the frequency (and thus the speed), they also control the current and thus the motor power. In the partial load range, this significantly increases efficiency, and by specifically designing the torque curve, it is also possible to replace slip-ring motors with induction motors.

The range of functions of a frequency inverter is essentially determined by the installed processor, which is why MOLL-MOTOR inverters are available at different price levels. A better processor enables higher control quality up to the servo controller, with which highly dynamic control of drives is possible and complex motion tasks, e.g. of robots, can be executed.

In order to control precisely, the current position of the drive must be known. For this purpose, resolvers or encoders (rotary encoders) are used that feed data back to the inverter. Incremental encoders, which record the movement in steps, are widely used. If the exact position must be known even after a power failure, absolute encoders are used. All designs commonly used in industry are available from us (inductive, capacitive, single turn, multi-turn, etc…).

Business customers usually buy frequency converters from MOLL-MOTOR as part of a complete drive package with motor and gearbox. They usually install the frequency inverter in their control cabinet, but we can also plan and build the control cabinet for the customer, or provide frequency inverters for direct mounting on a motor. Since we can flexibly select exactly the right components from various suppliers, both fast delivery and the optimal interaction of inverter, motor and gearbox are ensured.

Bonfiglioli Vectron FrequenCY INVERTER

For MOLL-MOTOR, the preferred partner for frequency inverters is the German manufacturer Bonfiglioli Vectron. Our companies are connected through a long-standing business relationship and through close business friendships between our employees, which is why we have already brought many challenging projects to a good conclusion. Bonfiglioli Vectron offers:

  • Highly efficient control of asynchronous, PM synchronous and synchronous reluctance motors
    In contrast to inverters from many other manufacturers, not only three-phase asynchronous motors but also synchronous motors can be controlled.
  • Power range: 0.2-1200kW
    MOLL-MOTOR can supply frequency converters for drives up to 160kW from stock. Thanks to production in Germany, individual units up to 400kW can be delivered within a few weeks, and we already have experience with this. Up to 3 of these inverters can be connected in parallel, which means that outputs of up to 1200kW can be achieved.
  • Various types of protection, mounting and cooling
    Frequency inverters are available from MOLL-MOTOR in various protection types, the required protection type depends on mounting and cooling. In order to counteract heat generation, various cooling types are available, which we cover with standard design or supplementary options (e.g. water cooling, through-hole design, cold plate).
  • Integrated protection and safety functions
    The safety of machines such as robots is often ensured with enclosures or cages. Sometimes this is not desired, or not possible. Here, the use of sensors can provide safety at the same level. The sensors must communicate with the inverter in a particularly safe way, type tests of these functions are required.
  • High functionality
    No matter which application you want to automate, we look forward to hearing from you (e.g. Cyclic Synchronous Positioning mode through cubic interpolation). If the quantity is sufficient, special software is even available!
  • Connection to common fieldbus systems
    The modular design enables connection to the common fieldbus systems (PROFINET, CANopen, Modbus, VARAN, etc…) by plugging in the various communication modules.
  • Generous stocking at the Stockerau warehouse / worldwide availability

Your benefits from our expertise and the manufacturer’s many years of experience:

  • Advice on system selection with motor and gearbox (consistent drive package)
  • Selection of equipment according to your application needs
  • Support from the first tests to series production
  • Commissioning support: both remotely and on-site